Lead extrusion apparatus



' Aplrfi 18, 1933.

F. q... DAVIS, JR LEAD EXTRUSION APPARATUS Filed June 4, 1932 1 asheetssheet 1 April 18, 1933. F. L. DAVIS, JR

I LEAD EXTRUSION APPARATUS :5 Sheets-Sheet 2 Filed. June 4, 1932 Illlll'llllul I attorneys April'lS, 1933. F. L. DAVIS, JR

' I LEAD EXTRUSION APPARATUS I Filed June 4, 1952 3 Sheets-Sheet 5Patented Apr-.18, 1933 UNITED STATES PATENT OFFICE FRANK L. DAVIS, JR.,OF KENILWORTH, NEW JERSEY, ASSIGNOR TO THE WATSON- STILLMAN 00., OFROSELLE, NEW JERSEY, A CORPORATION OF NEW JERSEY LEAD EXTRUSIONAPPARATUS Application filed June 4,

This invention relates more particularly to the extrusion of lead toform a sheathing for an electric cable.

An important object of the invention is to provide, in an extrusionapparatus of a certain type, means to effectually exclude air from theextrusion metal from the time it leaves a supply source in a moltenstate until it is extruded, and thereby prevent oxidation of the metaland, consequent flaws in the cable sheathing.

Another important object of the invention is to provide means to affordready access to the spaces in the apparatus from which air is excluded.

Other objects of the invention will appear hereinafter.

In the drawings, Fig.1 is a view showing the extrusion press intransverse section and the metal pouring means in longitudinal section,the view being on the line 11 of Fig.

Fig. 2 a section approximately on the line 22 of Fig. 1;

Fig. 3 an enlarged section approximately on the line 3-3 of Fig. 1;

Fig. 4 a section on t e line 44 of Fig. 3;

Fig. 5 a section on the line 55 of Fig. 2;

Fig. 6 an enlarged detail section on the line 66 of Fig. 3;

Fig. 7 an enlarged detail section on the line 77 of Fig. 5; and

Fig. 8 a detail sectional view showing one of the cleaning out openingsand its closure means.

The invention is shown in connection withv a form of extrusion pressknown as a straight through press wherein the extrusion chamber and theextrusion ram surround the cable to be sheathed and the ram operateslongitudinally of the cable. This press includes an extrusion unit orhead and a hydraulic pressure mechanism disposed in tandem relationlongitudinally of the cable and anchored together in fixed spacedrelation by tie bolts.

The extrusion head of the press includes a cylindrical block 1 having acentral bore 2 At one end said bore is tapered and opens into a re-1932. Serial No. 615,332.

duced cable passage 3. Iii the latter is fitted the annular extrusiondie 4 and opposed to the die is the extrusion point 5. The space betweenthe point and die determines the thickness of the cable sheathing. Atubular point holder 6 supports the extrusion point and has a threadedplug end 7 screwed into the cylinder. Adjacent said plug the bore 2 isenlarged, as at 8. A charging passage 9, formed in the cylinder, extendstransverse- 1y approximately tangential to the upper side of the bore 2and hasa restricted communication with the bore. Within the bore is anannular extrusion ram 10 snugly fitting both the bore and the pointholder 6 and reciprocable therealong.

The hydraulic pressure mechanism includes a hydraulic cylinder 11 and apiston 12 mounted to reciprocate therein.

cured to the outer end of the cylinder 11 is a smaller cylinder 13having a pull-back piston 14 reciprocable therein. A tubular stem 15connects the pistons 12 and 14 and alines with a central bore in thepiston 11. Ex-

tending through said stem and passage is a tube 16 which is connected atits inner end to the tubular point holder 6 and combines therewith toform a conduit for the cable U to be sheathed. The ram 10 has legs 17extending through apertures in the plug end of the point holder and inthreaded connection with the hydraulic piston 12. By admission ofhydraulic pressure through a pipe 18 to the cylinder 11, the piston 12isshifted to force the ram on its extrusion stroke and by admission ofpressure through a pipe 19 to/ the cylinder 13 the pull-back piston 14is shifted outward to retract the piston 12 and the ram.

Between the extrusion cylinder 1 and the hydraulic cylinder 11 there isan annular spacing structure formed of a single casting and comprisinghexagonal rings 20 and 21 abutting-the cylinders 1 and 11 respectively,

and connected by spacing sleeves 22 spaced screwed thereon.

the ring 24 aline with the spacing sleeves 22, and sleeves 26 integrallyformed on the hydraulic cylinder 11 aline with the sleeves 22 and 25.Through all of said alining sleeves are passed heavy stay rods or bolts27 threaded at their opposite ends and having nuts 28 These bolts anchortogether the extrusion head and the hydraulic mechanism. They haveshoulders 29 abutting the rings 20 and 24. For operation the ress willbe supported in a position with its cable conduit either horizontal orslightly inclined. I I A covered hopper 30 serves as a container formolten lead. The representation of this hopper is diagrammatic. Inpractice it will have heating means for fusing the lead and means forcharging it with pig lead. I have rovided meansfor delivering moltenlead rom the hopper to the charging passage 9 of the extruslon cylinderwithout exposure to air. At its lower end the hopper has a dischargeport 31 which ma be opened and closed by a slide valve 32. X casing 33fixed to the hopper forms an airtight chest enclosing said valve andport. An airtight conduit leads from said chest. The conduit includestelescoping tubular sections 34 and 35 with suitable packing 36therebetween. Between the conduit section 34 and the .chest there is anairtight hinge connection including a spherical member 37 fixed tooneend of the conduit section and rotatably fitted in an annular seat 38formed on the chest'and provided" with suitable packing means 39. Fixedto the outer end of the conduit section 35 is a closure disk 40 to closethe charging passage 9. Secured to the extrusion cylinder 1 is anannular casing 41 surrounding the mouth of the passage 9 and forming anextension of the passage. Said casing has a beveled outer edge bearing agasket, and the closure disk 40 has a beveled edge to fit against saidgasket and form an airtight jmncture. A suitable releasable clampingdevice 42 serves .to hold the closure disk tightly seated.

A tubular casing surrounds the tubular conduit and is also formed oftelescoping sections 43 and 44 fixed respectively to the conduitsections 34 and 35. This -outer casing defines a space surrounding theconduit and in said space is suitable means to heat the conduit. In thepresent instance the heating means comprises a gas burner 45.

The conduit sectlon 35 has an extension spout 46 leading from thedelivery end thereof and extending inward through the charging passage 9to the restricted discharge port of the passage. Between the spout andthe conduit there is a hinge connection 47. When the closure 40 isreleasedfrom its seat the conduit may be telescoped to retract it andmay be swung upward out of alinement with the passage 9 to give accesstothe latter.

The hinge 47 permits flexure between the conduit and the spout' so thatthe conduit may be swung upward without full withdrawal of the spoutfrom the casing 41 which forms part of the passage 9. For telescoping,the conduit there a gear rack 48 fixed at o'nefend'to the'closure and aear 49 meshing with the rack. The gear is ed to a shaft 50 mounted.in.bearings fixed to the outercasing section 43 and a crank 51 is fixedtosaid shaft for turning it."

For swinging the conduit upward there is' a weight 52 attached to oneend of-a tension strand 53, trained over elevated pulleys 54 andattached, as at 55, to the casing section 43. There is also a smallerweight 56 to restore and hold: the extension spout -46 in extendedposition when the conduit is s down to operative position. The hinge ofthe spout includes a pintle 57 to which is fixed a toothed segment Arack 59 meshes with said segment'and has astem extending outward andslidably fitted in a stufiing box 60 on the closure 40. Attached to thestem is a tension strand 61 trained longitudinally of the conduit,around 2:; 111- ley 62 mounted on the ca section 43, upward around avpulley 63 iiiiTo'ver pulleys 64 and downward and attached to the weight56. A stop finger 65 on the extension spout is engageable with anadjustable stop screw- 66 on the closure 40to limit the swing of thespout under the pull of the weight 56.

hisv

When the conduit is to be swung upward the clamping device'42 isreleased and the.

crank 51 is turned to shorten the conduit,'retract the closure 40 andpartly withdraw the extension spout; 'Theweight 52acts to elevate thereleased conduit and the free end of the spout enga es the interior ofthe casin 41 and causes exure between the spout .an

conduit, as indicated in Fig. 1 by dot and dash lines. Shortening of theconduit by 10-" tation of the crank 5]. permits the weight 56 to drop toits lowermost position and rest' upon a support. Then. as the conduit isswung upward the tension 6n the strand 61 is relieved by movement of thepulley 621:0-

. ward the pulley 63. This" permits the s ut to flex without resistanceby the weight; When the conduit and spoutare elevated, access to thepassage 9 for cleaning is unobstructed. As the conduit is swung downwardtension is re-aplplied to" the strand 61, the spout is guided ack intothe passage!) by engagement with the casing 41, and the weight 56restores the spout to extendedposition. The downward swing of theconduit is limited by a screw stop 66' mounted on an extension of thechest 38. By rotation'of the crank 51 the closure 40 is re-seated andthe spout 46 is thrust inward to livery position.

The lower side of the charging passage 9 slopes outward to an' overflowport 67 at the iso properdei so under side of casing 41. A tubulardischarge spout 68 leads downward from said port andforces the flapvalve open.

In the operation of the press, lead shavmgs are often forced past theram 10 and accumulate in the enlarged portion 8 of the bore 2. Forcleaning out this space the cylinder 1 is formed with a number ofapproximately radial cleaning out openings 71. In the present instancethere are three of these openings, two leading downward and one upward.For each opening there is a beveled closure disk 72 seated in a beveledseat at the periphery of the cylinder. Each closure 72 is held seated bya toggle device. The latter includes a split ring 73 encircling one ofthe tie bolts 27 and rotatable thereon. A link 74 is pivoted at one endto said ring and at its opposite end to the closure and provided with ahandle. The pivotal connection between the link and closure includes athreaded shank 75 screwed into a threaded bore in the link and providingfor proper adjustment between pivot centers in the assembly of thetoggle device. \Vhen the toggle is almost on dead center it holds theclosure seated and airtight. The closure is quickly unseated and swungopen by graspin the handle and breaking the toggle. Stops 75' on thelink 74 and on the ring 73 prevent the toggle frombeing shifted pastdead center.

In order to prevent air leakage inward through the apertures in the plugend of the point holder 6, past the ram and into the extrusion chamber,the space 77 between the rings 20 and 21 of the annular spacingstructure is enclosed by panels 78 screw fastened to said annularstructure. The lowermost panel has a cleaning out aperture 79 closed bya screw fastened plate.

After each extrusion operation there is a residueof the lead left in theouter end of the extrusion chamber and sealing it. There is then acontinuous airtight space including the valve chest 33, the tubularconduit, the

charging passage 9, the extrusion chamber 2 and the enclosed space 77 inthe annular spacing structure. Means are provided for charging thisspace with a non-oxidizing gas from a suitable source diagrammaticallyrepresented in the drawing by a tank 80. I prefer to employ pure, orapproximately pure, nitrogen gaswhich is non-oxidizing andnon-combustible and will not be injurious to the workmen if it escapes.'From the tank a supply pipe 81 leads to the valve chest 33. This pipe isformed in two sections joined by a chest 82. The latter has a springseated blow-off valve 83 and a screen 84 separating the pipe sections inthe chest. If

.of oxidation.

combustible impurities are introduced by the gas and become ignited bythe heat in the apparatus the screen will serve to prevent thecombustion from reaching the supply tank.- A manually operable valve. 85in the pipe 81 serves for controlling thev gas delivery.

In the operation of .the-lappara'psthe air is first evacuatedtherefromiby; opening the valve 85 and admitting the gas, at amaterially higher pressure than the atmosphere, to the chest 33. Thenceit flows through' the lead delivery conduit, through the chargingpassage 9, into the xtrusion chamber 2 and into the space 77 within theannular spacing structure by way of clearances around the ram and alsobetween the ram legs 17 and the apertures in the point holder throu hwhich the legs pass. If the outer end of t e extrusion chamber is sealedby a residue of lead the air will be expelled through the overflow spout68, the pressure of the gas being sufiicient to force open the weightedflap valve 69. Preferably spring seated blow-off valves 86 are alsoprovided on the casing 41, on the cleaning out closures 72 and on one ofthe panels 78 to permit the air to escape. The valve is kept open andthe gas charge is kept at a pressure exceeding that of the atmosphere toprevent leakage of air into the apparatus. If requlred, suitable meansmay be employed to keep the gas at just the proper pressure.

When the apparatus is thus charged with the non-oxidizing gas the valve32 is operated through a handle extending outside of the valve chest toadmit a charge of molten lead from the hopper to the delivery conduit tocharge the extrusion chamber through the passage 9. When the chamber isovercharged the excess lead flows out through the charging passage andthrough the'over-flow spout 68. When the discharge occurs the valve 32is closed. The charge of lead in the extrusion chamber 1s permitted tocool to the proper plastic consistency for extrusion, then the h draulicpressure mechanism is operated to orce the rain on its extrusionstroke.

From the time each charge of lead leaves the hopper until it isextruded, air is effectually excluded from it by the airtightconstruction and by the gas-under pressure, and oxidation of the lead isprevented. \Vhen, as in previous structures, the hot lead is exposed toair in an open delivery spout and in the extrusion chamber it oxidizesrap idly and causes flaws in the cable sheathing which often permitleakage of electric current. My improved apparatus enables an extrusionpress of the straight through type to produce a strong, uniform,homogeneous cable sheathing free from the flaws It also enables theairtight spaces to be readily opened for frequent cleaningto remove leaddeposits, as previously described. While the invention is parhydraulicpiston 12 the volume of said space and consequently the pressure of thegas therein will vary with the different posit-ions of said piston. Inorder to augment the volume of said space andreduce the variation in gaspressure a tank 87 may be connected with said space through a pipe 88.Said space also has a drain pipe 89 leading to a trap, To preventleakage of gas from the space 77 and leakage of air thereto along thetube 16 the pull-back piston l is provided with a stufiing box 90fitting around the tube.

Features of invention disclosed but not claimed in this application areclaimed in my co-pending application Serial No. 609,818 filed May 7,1932.

What I claim is':

1. In a metal extrusion apparatus including an extrusion chamber havingan airtight charging and cleaning out passage, an extru-- sion rammounted to reciprocate in the extrusion chamber and a supply containerfor molten metal having adischarge port, an

airtight delivery rconduit leading from said of alinement with thecharging passage when it is freed from the latter. 2. In ametal'extrusion apparatus includmg an extrusion chamber having anairtight charging and cleaning out passage, an extru- P r and comprisingtelescoping tubular sect1ons;

sion ram mounted to reciprocate. in the extrusion chamber and a supplycontainer for molten metal. having a discharge port, an airight deliveryconduit leadin from said supy discharge port to said c arging passagemeans excluding air from said discharge port and the adjacent end ofsaid conduit; an airtight releasable juncture between said conduit andsaid charging passage, the conduit being retractible from the passa e bytelescoping; a hinge mounting fort e conduit adapting it .to be swungout of alinement ing an extrusion chamber having an airtightcharging andcleaning out passage, an extrusion ram mounted to reciprocate in theextrusion chamber and a supply container for 1 molten metal having adischarge port, an airtight delivery conduit leading from said supplydischarge port to said charging passage and comprising telescopingtubular sections; means excluding air from said discharge port and theadjacent end of said conduit; an airtight releasable juncture betweensaid conduit and said charging passage, the conduit being retractiblefrom the passage by telescoping; and a hinge mounting for the conduitadapting it to be swung out of aline ment with the charging passage;

4. In a metal extrusion apparatus including an extrusion chamber havinga charging and cleaning out passage, an extrusion ram mounted toreciprocate in the extrusion chamber and a supply container for moltenmetal having a discharge port, an airtight delivery conduit leading fromsaid discharge port to said charging passage and comprising telescopingtubular sections; an. air-excluding chest surrounding said dischargeport; an air-tight hinge connection between the adjacent'end of theconduit and said chest adaptingthe conduit toswing vertically; anairtight releasable juncture between the opposite end of the conduit andsaid charging passage; an extension spout hinged to the conduit andextending through said charging passage; rack and pinion means carriedby the conduit and operable to telescope the conduit-to retract thelatter from the charging passage; a weight operatively connected to theconduit to swing it upward out of alinement with the charging passage,the hinge connection between the conduit and extension spout permittingsaid u ward swing of the conduit without full with rawal of the spout;and a' weight operatively connected to the extension spout to swing thelatter about its hin e to operative position when the conduit 1srestored to operative position.

5. In a metal extrusion apparatus including an extrusion chamber havinga charging and cleaning out passage, an extrusion ram mounted toreciprocate in the extrusion chamher and a; sup 1y container for moltenmetal chest surrounding said discharge port; an

air-tight hinge connection between the adj afvcent end of tlie conduitand said chest adapting the conduit to swing vertically; an airtightreleasable juncture between the opposite end of the conduit and saidcharging passage; an extension spout hinged to the conduit and extendingthrough said charging passage; rack and'pini'on means carried by theconduit and operable to telescope the conduit to retract the latter fromthe charging passage; a weight operatively connected to the conduit toswing it upward out of alinement with the charging passage, the hingeconnection between the conduit and extension spout permitting saidupward swing of the conduit without full withdrawal of the spout; aweight operatively connected to the extension spout to swing the latterabout its hinge to operative position when the conduit is restored tooperative position; and means to charge said chest, conduit, chargingpassage and' extrusion chamber with a non-oxidizing gas.

6. In a metal extrusion apparatus including an extrusion chamber havinga charging and cleaning out passage, an extrusion ram mounted toreciprocate in the extrusion chamber and a supply container for moltenmetal having a discharge port, an airtight delivery conduit leading fromsaid discharge port to said charging passage and comprising telescopingtubular sections; an air excluding chest surrounding said dischargeport; an air-tight hinge connection between .the adjacent end of theconduit and said chest; an airtight. releasable juncture between theopposite end of the conduit and .said charging passage; and an extensionspout hinged to the conduit and extending through said charging passage,the conduit being longitudinally contractible by telescoping to retractit from the charging passage and its hinge connections with the chestand with the extension spout adapting it to be swung out of alinementwith the charging passage without full withdrawal-of the extensionspout.

7. In a metal extrusion apparatus including an extrusion chamber havingan airtight charging and cleaning out passage and an extrusion rammounted to reciprocate in the extrusion chamber, an airtightdelivery'conduit leading to said charging passage and comprisingtelescoping tubular sections; an airtight releasable juncture betweensaid conduit and charging passage; an extension spout hinged to theconduit and extending inward through the charging passage, the conduitbeing retractible from the passage by telescoping it; a hinge mountingfor the conduit adapting it to be swung upward, when retracted, out ofalinement with the passage, the hinge connection between said extensionspout and the conduit permitting upward swing of the latter without fullwithdrawal of the spout; a weight connected to the conduit to swing itupward; a tension strand connected to the extension spout; a weightconnected to said strand to exert a tension thereon tending to hold thespout extended in normal operative relation to the conduit; and meanstrainingsaid strand and operative to relieve the tension thereon as theconduit is swung upward and thereby the delivery end of the conduitinward through the charging passage; and a hinge connection between theconduit and said spout permitting. the conduit to be swung upwardwithout full withdrawal of the spout from the charging passage; means toswing the conduit upward; and means to automatically restore the spoutto extended position in the charging passage when the conduit isrestored to alinement with said passage.

9. In a metal extrusion apparatus including an extrusion chamber havingan airtight charging and cleaning out passage, an extrusion ram mountedto reciprocate in the extrusion chamber and a supply container formolten metal having a discharge port, an airtight delivery conduitleading from said discharge port to said charging passage and comprisingtelescoping tubular sections; means to exclude air from saiddischarge'port and the adjacent end of the conduit; an air-tight hingeconnection between the adjacent end of the conduit and said chestadapting the conduit to swing vertically; an airtight releasablejuncture between the opposite end of the conduit and said chargingpassage; an extension spout hinged to the conduit and extendingtherefrom through said charging passage; and'rack and pinion meanscarried by the conduit and operable to telescope the conduit toretractthe latter from thecharging passage, the hinge connection betweenthe conduit and extension spout permitting said upward swing of theconduit while the discharge end of the spout remains in the chargingpassage.

10. In a metal extrusion apparatus including an extrusion chamber havingan airtight charging and cleaning out passage and an extrusion rammounted to reciprocate in the extrusion chamber, an air-tight deliveryconduit leading to said charging passa e and having an air-tightjuncture therewit means to enable introduction of molten metal into saidconduit and prevent introduction of air; and means for heating saidconduit.

11. In the combination of an extrusion mechanism comprising an extrusionchamber and an extrusion ram reciprocable in said chamber and a fluidpressure mechanism operatively connected to the ram and spaced from theextrusion mechanism and tie rods connecting said mechanism and holdingthem in spacedtandem relation, walls surrounding the tie rods anddefining an airtight chamber between said mechanisms and surrounding theram; means tocharge said chambers with a non-oxidizing gas; and

means to retain said gas in the extrusion chamber.

12. In an extrusion apparatus including an extrusion chamber, anextrusion ram mounted to reciprocate insaid chamber and a chamber backof the extrusion chamber and surrounding the ram, means to exclude airfrom said chambers to prevent oxidation of the extrusion metal, saidchamber back of the extrusion chamber having a cleaning out aperture; anair-tight closure for said cleaning out aperture; and toggle means to"hold said closure in closed position and operable to shift the closureto open position.

13. In an extrusion apparatus including an extrusion chamber, anextrusion ram mounted to reciprocate in said chamber and a chamber backof the extrusion chamber and surrounding the ram, means to exclude airfrom said chambers to prevent oxidation of the extrusion metal, saidchamber back of the extrusion chamber having a cleaning out aperture; anair-tight closure for said cleaning out aperture; toggle means to holdsaid "anism having an air-tight chamber between it and the fluidpressure mechanism and surrounding the ram and having a cleaning outaperture; an air-tight closure for said cleaning out aperture; andtoggle means for holding said closure in closed position and operableto' shift it to open position and including a ring encircling one of thetie rods and rotatable thereon and a link pivoted at one end to'saidring and pivoted at its opposite end to the closure.

15. In an extrusion apparatus for cable covering including a tubularcable conduit, a casing forming an annular extrusion chamber surroundingsaid conduit and having an approximately tangential charging passageleading to said chamber, an annular extrusion ram surrounding saidconduit'and mounted to shift through the extrusion chamberlongitudinally of the cable conduit, and fluid pressure operated meansto shift the ram, means defining an air-tight chamber signature. I FRANKL. DAVIS, JR.

